SNCA and Parkinson disease: In rare autosomal dominant inherited forms of PD, missense mutations in the α-syn gene (PARK1) result in amino acid substitutions Ala-53→Thr, Ala-30→Pro, Glu-46→Lys; in addition, duplication and triplication mutations in the α-syn gene (PARK4) have been found [322,323,324].